Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Pass Labs This forum is dedicated to Pass Labs discussion.

The BA-3 as preamp build guide
The BA-3 as preamp build guide
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 9th November 2018, 12:45 AM   #1211
anhton82 is offline anhton82  Viet Nam
diyAudio Member
 
Join Date: Dec 2017
Location: Vietnam
Quote:
Originally Posted by JeffYoung View Post
In a push-pull design the voltage the coupling cap is blocking is only the DC offset (ie: the difference between ground and the centre point of your push-pull). In an ideal world that would be 0 (and there would be nothing to block), but in practice differences between components (and in particular between complementary P and N pairs) means it can be a few volts.

The other thing to consider is what happens if one of your output MOSFETs fails. Depending on the failure mode the DC offset could rise to your + or - rail voltage.

So, even though the cap will normally only be blocking a few volts, it's best to spec it at your rail voltage. Since that's still well under 150V, the mentioned cap would be fine.

Cheers,
Jeff.
Many thanks for your detail explain. I'm a newbie. And this is my first DIY preamp, before that, I finished my first +_15V PSU ( Salas UltraBiB V1.3 ) for Allo Katana DAC. I'm glad to joining you guys DIY world.
  Reply With Quote
Old 9th November 2018, 07:34 AM   #1212
anhton82 is offline anhton82  Viet Nam
diyAudio Member
 
Join Date: Dec 2017
Location: Vietnam
And one more question, Can I use 100k Volume for this preamp?
Thanks !
  Reply With Quote
Old 9th November 2018, 02:18 PM   #1213
Russellc is offline Russellc  United States
diyAudio Member
 
Join Date: Mar 2003
Location: midwest
The BA-3 as preamp build guide
Quote:
Originally Posted by McQuaide View Post
Thanks, added to my Mouser project along with Silmics and MKPs to try.
I like one of Zenmod's favs, the Philips MKC very reasonable and sound very nice. Just ordered a bunch off Ebay in 1.0 and .1 uf for bypass duty.

Russellc
__________________
Pass B-1 preamp, Pass BA3 preamp, Pass F-5 Amp, Pass F-6 Amp, Pass BA-3 Amp, Pass M-2 amp, Pass Aleph J amp, Pass Pearl 2 Phono pre Tekton Enzo, Altec A7, Econowave JBL 2235H & B&C CD
  Reply With Quote
Old 9th November 2018, 04:33 PM   #1214
McQuaide is offline McQuaide  United States
diyAudio Member
 
Join Date: Jan 2011
Location: Southeastern Pennsylvania
Quote:
Originally Posted by WKCox View Post
+1 on the CDE polypropylene. I used these in a recent recap of my Audio Research / Dynaco ST-70-C3 with excellent results.

I'd like to put these for my Fisher tube amp in .047uF but all they have is 2KV - is there any disadvantage to using a 2KV cap to replace a 400v?
__________________
Mark
  Reply With Quote
Old 9th November 2018, 04:36 PM   #1215
ggetzoff is offline ggetzoff  United States
diyAudio Member
 
ggetzoff's Avatar
 
Join Date: Nov 2004
Location: Southwest
The BA-3 as preamp build guide
Quote:
Originally Posted by McQuaide View Post
I'd like to put these for my Fisher tube amp in .047uF but all they have is 2KV - is there any disadvantage to using a 2KV cap to replace a 400v?

Higher cap service voltage is fine. Probably lower ESR.
__________________
Airline Pilot-If it's not Boeing I'm not going.
Aleph J, DCB1, VHEX + USSA-5, BA-3 Pre, DCG3,USSPA
  Reply With Quote
Old 15th November 2018, 07:27 AM   #1216
sergiog is offline sergiog  Italy
diyAudio Member
 
Join Date: Aug 2013
Location: Italy
Hi, I kindly ask for information, having available 2 matched pair of K170 / J74 for 10.5 mA (of an old project), can I get lost or I have to change the value of the resistance? Thank you very much
  Reply With Quote
Old 15th November 2018, 07:28 AM   #1217
Zen Mod is offline Zen Mod  Serbia
Official Court Jester
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
The BA-3 as preamp build guide
you can use them
__________________
my Papa is smarter than your Nelson !
clean thread; Cook Book;PSM LS Cook Book;Baby DiyA ;Mighty ZM's Bloggg;Papatreasure;Papa... by Mighty ZM
  Reply With Quote
Old 19th November 2018, 08:28 PM   #1218
McQuaide is offline McQuaide  United States
diyAudio Member
 
Join Date: Jan 2011
Location: Southeastern Pennsylvania
I'm planning to use a Silmic II in C3 with a .1uf film. How do I orient the polarity of the Silmic? There is a + on the output side on the PCB, but the Pearl 2 schematic has the + sign on the circuit side.
__________________
Mark
  Reply With Quote
Old 19th November 2018, 08:36 PM   #1219
Zen Mod is offline Zen Mod  Serbia
Official Court Jester
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
The BA-3 as preamp build guide
output node (inner side - pre cap) of BA3 FE is approx at 0V , if you set so ....

next stage potential ( amp input) is presumably on same level

so - how you are going to orient Silmic is irrelevant
__________________
my Papa is smarter than your Nelson !
clean thread; Cook Book;PSM LS Cook Book;Baby DiyA ;Mighty ZM's Bloggg;Papatreasure;Papa... by Mighty ZM
  Reply With Quote
Old Yesterday, 03:47 PM   #1220
McQuaide is offline McQuaide  United States
diyAudio Member
 
Join Date: Jan 2011
Location: Southeastern Pennsylvania
I'm setting P3 and one pot equals out at 47.5 ohms and the other equals at 50.7 ohms. Measuring from pins 1-2 and 2-3. Is this OK?
__________________
Mark
  Reply With Quote

Reply


The BA-3 as preamp build guideHide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
BA-3 As Preamp vdi_nenna Pass Labs 1322 16th July 2018 01:23 AM
MyRefC build guide AndrewT Chip Amps 1119 29th July 2016 11:30 PM
Trapezoid build guide? mudchute Planet 10 hifi 22 10th November 2014 10:37 AM
MY FIRST BUILD BA-1 joesch1999 Pass Labs 15 15th May 2011 09:54 PM
FS: two burning amps (one each BA-1 and BA-2) without drivers Eric Weitzman Swap Meet 15 17th February 2010 03:35 AM


New To Site? Need Help?

All times are GMT. The time now is 12:28 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki